Hydraulic circuit apparatus



June 12, 1951 c. ROTTER ETAL 2,556,708

HYDRAULIC CIRCUIT APPARATI JS Original Filed March 13, 1944 FIGI. FIGZ.

4 Sheets-Shet l ma a3 June 12, 1 5 c. ROTTER ET AL HYDRAULIC CIRCUIT APPARATUS 4 Sheets-Sheet 2 Original Filed March 13, 1944 4 Shee'ts-Sheet 3 L C ROTTER ET AL HYDRAULIC CIRCUIT APPARATUS June 12, 1951 Original Filed March 13, 1944 J1me 1951 L. c. ROTTER ETAL HYDRAULIC CIRCUIT APPARATUS 4 Shets-Sheet 4 Original Filed March 13, 1944 Patented June 12, g 1951 'Klein,.St. Louis, Mo., assignors to Lincoln Engineeri'ngCompan-y, St. Louis, Mo., a corporation of Missouri Original application'March 13, 1944., Serial'No. 526,160, now Patent No. 2,399,573, dated April 30, 1946. 'Divided and this application April1'6, 1945', Serial No..588,452

31=Claims.. (Cl. 277-20) This invention relates to hydraulic circuitapparatus, and with regard to certain'morespecific features, tohigh-pressure-apparatus of thisclass.

The invention is a division of the invention described in our United'States Patent 2,399,573 dated April 30, 1946, for HydraulicCircuit Apparatus.

Among the several objects ofthe invention may be noted the provision of hydraulic apparatus and. the hydraulic circuit formed thereby for commerciallyproducin-g extremely high unit pressures (for example 25,000 p. s. i.) for hydraulic testing purposes, and liquid supplies for hydraulic presses, hydraulic machine tools and the like; the provision of apparatus and a circuit of the class described which will quickly produce said pressures in cases where high bulk factors exist in the apparatus requiring the pressures; the provision of apparatus of this class which will hold the stated high pressure indefinitely even with leakage in the apparatus served; and the provision of means of the class described which is reliable, compact, safe and'ioolproof, and which will remain soover a long life. Other objects will bein part obvious and in partpointed out hereinafter.

The invention accordingly comprises the elements and combinations of elements, features of construction, and arrangementsof parts which will be exemplified in the structures hereinafter described, and the scope of the application of which will be indicated in the following claims.

In the accompanying drawings, in which is illustrated one of various possible embodiments of the invention, 7

Fig. 1 is a side elevation of apparatus embodying the invention;

Fig. 2 is an enlarged top plan view of Fig. 1;

Fig. 3 is a fragmentary front elevation (viewed from the right of Figs. 1 and 2.) drawn on the scale of Fig. 2;

Fig. 4 is an enlarged, detailed plan view of a valve control'block, being viewed substantially from line 4-4 of Fig. 3;

Fig. 5 is a horizontal section through said control block, being taken on line 5-5 of Fig. 3;

Fig. 6 is a left-side elevation of Fig. 4, being viewed from line 6-45. of Fig. 4;

Fig. '7 is a horizontal sectional view of a control valve, being taken substantially on line 1-i of Fig. 3;

Fig. 8 is a vertical section taken through a high-pressure pump element, the section being taken on line 8--8 of Fig. 3;

Fig. 9 is an enlarged detail. section. of an outlet header l1.

2 check valve assembly for ahighpressure pump; and,

Fig. 10 is a circuitdiagram.

Similar reference characters indicate corresponding parts throughout the several views of the drawings. a

The hydraulic. system and apparatus of the present invention are adapted commercially to produce a high working pressure (up to 25,000. p. s. 1.) operating froma low pressure air supply (of the order of 100 p. s.-i.) This end is attained without any substantial; danger-of explosion andat high volumetric capacity- Referring now more particularly to. Figs. 1-3, there is shown at numeral l-a. framework supporting a tank 3. The latter'carries liquid up to: a level such as shown at Lin Fig.3. The exact level is not important, since it is primarily the measure of the amount of fluid carried in the tank (40- lbs., for example)- The liquid may be oil or light grease. At the bottom of the tank is an outlet connection 5 which through a- -'F' 1 has one branch 9 leading to a-isolidsteel highpressuredistributor and-control block H. The, other branch of the T 1 leads to a drain cock l3 which is normallyclosed but which may be opened for drainage and chargingoff the tank, and for removing sedimentation of solids, or moisture due-to condensation.

Above the liquid level L the tank 3 carries air, an inlet i5 being provided for its introduction. This inlet is connected by a branch pipe i9: to an air header H. Another branch '21 leads from the header H to the inletof a first. reciprocating air engine 23.. A thirdbranch 25 from the header l1 leadsI to a second reciprocating air engine 2-1. In the branch line 25 is a manually controlled regulator valve 29 and a suitable pressure gauge 3|.

The header I! receives its air through a threeway valve, 33 from an air inlet line 35. The air line 315 carries air pressure at, for example, 100' p. s. 1. pressure. This is an ordinary valve availablefrom many air compressor supply companies. The valve 331 (Figs. 3 and 7) has an exhaust outlet 31 and a. rotary plug 39 in which isathre'eway port '4l. Plug 39 isoperated by handle M). In the position of the valve plug shown in Fig. 7 air may pass from the supply pipe 35 to the By rotating the plug counterclockwise, the air'supply may be cut off and the header I! connected with the exhaust 37. Thus by opening the. valve 33 air may be supplied to the tank 3 above the liquid therein at 10.0 p. s. i. It. is also supplied at that same pressure to. the

first air engine 23 and to the second engine 2'! at that or a lower pressure, as determined by the regulator 29.

Each air engine 23 and 2'5 is of the general type disclosed in United States Patents 2,215,852 and 2,269,423, dated September 24, 1940 and January 13, 1942, respectively. Further description it is believed will be unnecessary in View of the showing in these patents, except to state (see Fig. 10) that engines 23 and 21 have reciprocating, doubleacting, air-operated pistons 25 and 28 respectively to which air is distributed for double action by means of valve gears 43 and 54 respectively. The total pressure exerted by each piston under a given air pressure is proportional to its area. The area of the piston of engine 23 is smaller than that of the piston of engine 21.

The piston 24 of engine 23 is connected to the plunger I of a well type of hydraulic pump indicated broadly at 45. The pump 45 extends down to a point near the bottom of the tank 3, where it has its inlet check valve i8 always submerged for all normal variations in the level L. Associated with plunger I6 is a valve 20. Pumps of this class operated by air engines similar to 23 are known and will not be further described (see, for example, United States Patent 1,970,591, dated August 21, 1934). The outlet of the pump is indicated at 49. This outlet is connected by means of pipe 5I with the control block II. The piston of air engine 21 is connected to the piston of a hydraulic booster pump indicated broadly at 4?, the details of which are shown in Fig. 8.

Details of the control block II are shown in Figs. 4-6. It consists of a solid steel piece in which is an outlet manifold 53 to which is connected an outlet pipe or service connection 55. This pipe 55 is connected with the device or machine to which liquid pressure and volume are to be supplied, which may be a device to be tested for high pressure, or a hydraulic press or other machine. This control block has an inlet passage 5'! to which is connected the line 9 leading from the liquid tank 3. In a cross passage 6| is a new type of check valve 59 especially adapted to the high pressures involved.

Valve 59 consists in a cylindric counterbore 63 in passage BI, at the bottom shoulder 65 of which counterbore is seated a disc 6'! having openings 69. This disc is recessed as shown at H for producing a ledge I3. This ledge I3 provides the seat for the endmost of a series of accurately made ring seats I5, each of which seats enclwise on another and each of which has an interior conical opening or chamber 1'! rounded at its small end as shown at I9. Accurately seating balls 8| are carried within the conical openings I1, separated from one another when seated. These, under unbalanced pressure from 53 to 5'! rest upon the seats. Under unbalanced pressure from 5'! to 53, they unseat and form a stock in contact. A gland nut 83 serves to press together disc 5'! and the ring seats 75. Nut 85 is counterbored as indicated at 85 and provided with openings 8! to the counterbore so that fluid may fiow from inlet 51' through the valve 59 to the outlet 55, unseating the balls M as it does so. However, the balls are prevented from escaping by the disc 57. The space between the endmost ball and the disc 51 is less than the movement of the balls which would bring about reclosing of the balls on the rounded ends 59 when. opened.

Passing through the nut 33 is a threaded, rotary, operating stem 35, packed as indicated at 9i and having a nose portion 93 which may contact the lowermost one of the balls 5|. A cross pin prevents the stem 89 from being unthreaded too far. Outside, the stem 89 carries a crank handle 9? and between it and the nut 83 is a tubular spacer 59 which permits the operator to screw the stem forward only enough to cause unseating of the balls El without pressing the endmost one into engagement with member 51.

The counterbore 63, disc 51, ring seats I5 and balls BI are made to a high degree of accuracy including lap fits where necessary to prevent leakage. The balls and the conical seats I? are arranged so that upon closing the valve the upper ball seats first, then the second, third and fourth successively. Upon opening the valve the lowermost ball opens first and then the others in serial order, the uppermost opening last. The advantage of such a construction is that as the endmost ball comes toa seat under high pressure, all of them gradually exert increased throttling action without all seating at once. This reduces the cutting action of fluid in passing between the balls and the seats. When the balls open, the upper one unseats last, the others having already opened in serial order.

At numeral I5! is sown another valve similar to the one just described in which like numerals designate like parts. The holding nut I03 for this valve difiers from the nut 83 in that it has no operating stem through it. This valve MI is in a passage I05 which leads to the outlet manifold 53.

A passage Iill' is connected through the openings 87 to the inside of the nut I03. It is this passage till on the inlet side of the valve IElI to which is connected the pipe 5! from the pump 45. This passage iii? is also connected by means of a pipe I 59 to the inlet II! of the booster pump 5? above-mentioned (Fig. 8). The plunger of this pump is shown at H3 and is connected with the piston 28 of the reciprocating air engine 27.

The outlet N5 of the pump 4'! is connected to the outlet passage 53 in the block II and provides a high-pressure inlet to the block. A special outlet check valve H7 is used in pump ll and consists in a threaded thimble H9 counterbored as shown at I2! to receive a series of closely dimensioned rings I23 having oppositely countersunk openings I 2!) therethrough. Balls I25 are trapped in the spaces left by the countersinks and seat on the bottoms of openings I20 in a direction to allow flow from the pump but to resist back flow of fluid to the pump. Milled slots 55 prevent the balls from seating on the upper ends of openings !2Il when flow is from recess I25. Each ring has a ledge I22 at one end for telescoping with a shoulder I24 of its neighbor. Copper packing washers I3I are used between the ledges H2 and shoulders H4. The last ring toward the pump telescopes recess I26 and seats on a copper washer I28. The last ring in the other direction seats on a copper washer I28 in the bottom of the counterbore i2 5. Axial pressure from threading home the thimble H9 seals together all of the rings I23.

Fig. 10 will aid in following the operation which is as follows, assuming that the tank 3 has been filled up to the level L with suitable liquid. Crank 5? is backed off from the position shown in Fig. 5 to allow valve 53 to operate automatically. The necessary connection with the apparatus to be supplied with pressure is made through line 55. Air at p. s. i. or so is supplied from the pipe 35 and the valve 33 is opened as indicated in Figs. 7 and: 10. This supplies air at 100 p. s. iron the surface of the liquid in the tank 3. It also supplies air at this pressure to the air engine 23-. and air under pressure to the engine 2?. The regulator 29. is set for an air pressure which when operating on the booster pump ll will produce the ultimate hydraulic pressure desired in line 55.

Pressure of. air on the liquid in the tank 3 quickly forces it out involume to the inlet 51 of the block ll. The pressure automatically opens the valve 55 and fiow occurs through the outlet manifold 53 to the supply line 55. This quickly fills the apparatus to be tested even though it has a high bulk factor. This is because the displacement of air into tank 3 and displacement of liquid therefrom may bequite fast.

At the same time the engine 2:3 starts automatically due to the air pressure supplied: to it. This reciprocates the pump45. Whichdraws fluid from the bottom of the tank and forces it out through the line 5!. Thus it is delivered-to-port i! in the block H, from whence it passes through the check valve [ill to the outlet 53 and also to the line 55.

When, due to-filling meet the apparatus connected with 55, the reaction pressure in the pipe 55 becomes greater than the unit pressure on the liquid inthe tank 3 (100 p. s. i.), the valve 59 automatically closes and the pump 45 con- 'tinues to supply pressure through the valve Hill.

The pump 45 and engine 23 are capable (for example) of running the pressure up to 2,000 p. s. i. Pump 45 may be considered to be a primer pump. The pressure of 2,000 p. s. i. is determined by the relative areas of the engine piston and pump plunger.

During the operating period above described, the engine 21 has also received air and has been operating its pump 41 which supplies fluid at the connection H of the block II. Thus this pump 41 also supplies fluid to the outlet manifold 53 and hence to the pipe 55. The pump 4? receives its supply from the primer pump 45 via pipe 5!, port I01, line W9 and port Hi. The area of the piston in engine 21 and the area of its pump plunger are so related that pump 4'1 generates about 25,000 p. s. i. hydraulic pressure. Thus, as the reaction pressure in line 55 builds up past the 2,000 p. s. i. value of pump 23 the valve HH also closes and thereafter the pipe 5! from pump 45 supplies only the pump 4'5 via line E09. Pump 5? at all times acts as a booster pump for the primer pump 45. Thus the pump 51 continues to build up pressure, both valves 59 and I0] being closed, until the pressure in the line 55 reaches the stated value of about 25,000 p. s. i. The exact value is determined by the setting of the regulator 29 which controls the unit air pressure applied to the piston of the engine 21.

At this point it will be clear why the valves 55 and i5! need to be of improved construction. No ordinary check valve would be able to last long under a pressure difierence between 25,000 p. s. i. in the manifold 53 and the 100 p. s. i. in the port 57 (in the case of valve 55) nor the pressure difference between 25,000 p. s. i. and the 2,000 10. s. i. in the port I01 (in the case of valve The engines 23 and 21 automatically stop when the pumps 45 and 41 respectively reach pressures of 2,000 p. s. i. and 25,000 p. s. i. For example, the ratio of areas of the pistons in engine 23 and pump 55 is :1, thus producing from 100 lbs. air

pressure approximately 2,000 p. s. i. In the case of the booster engine 21, the ratio of its piston area to the area of theplunger H-3in pump 411s 370:1 which gives a margin for adjusting down to bring the hydraulic pressure back up. When engine 21 starts, engine 23 also starts because the requirements of pump 4! incipiently drop the pressure in line 5|.

Upon completion of a testing or operating cycle, the three-way air valve 35 is moved to its exhaust position, thus exhausting air from the pressure tank and from the engines 23 and 21. The

crank Bl is then rotated to the position shown-in Fig. 5 against the limiting stop 99. This opens the check valve 59 and hydraulic fluid bleeds back through the check valve 59 and returns. to the pressure tank.

The present invention is an improvement over prior schemes for the purpose, since it introduces an intermediate-pressure filling operation after a low-pressure filling operation and before the highest pressure is applied. Thus'not only does it take care of bulk factor due simply to the requirements of volumetric filling, but bulk factor (due to stretching under substantial pressure) of the physical parts of the system, including the apparatus served. Loss of time is avoided that would be involved in taking up the last-mentioned bulk factor by'means of the high-pressure application. In other words, the air pressure in tank 3 quickly causes filling of the system, the intermediate-pressure primer pump quickly stretches the physical parts of the system under the 2,000 lbs, pressure, and the booster pump completes the high-pressure application. If the higher-pressure booster pump 41 were to operate alone throughout the pressure range that the intermediate-pressure pump now does, the time required for a cycle of operation would be much longer due to the necessarily low volumetric displacement of pump 41.

The apparatus is safe, since no pressures higher than p. s. i. or so are applied to the tank 3.

It is to be understood that, although air pressure is used, other gases under pressure may be employed and the terms air and gas are to be understood as being synonymous. Also other liquids besides oil may be employed, such as hydraulic brake fluid, water, alcohol, all being equivalents for the purpose of the invention.

In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained.

As many changes could be made in the above constructions Without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

We claim:

1. High-pressure hydraulic apparatus comprising a pressure block, said block having an outlet manifold and a low-pressure inlet passage connected thereto, a first check valv connecting said inlet passage with said outlet manifold, said check valve opening only downstream from the inlet passage to the outlet manifold, a second intermediate-pressure inlet having a connection with said outlet manifold, a second check valve in said last-named connection, a second intermediatepressure outlet communicating with said second inlet, and a third high-pressure inlet connected with said outlet manifold, said third inlet bein with respect to said second inlet on the downstream side of said second check valve.

2. High-pressure hydraulic apparatus comprising a pressure block, said block having an outlet passage and a low-pressure inlet manifold connected thereto, a first check valve connecting said inlet passage with said outlet manifold, said check valve opening only downstream from the inlet passage to the outlet manifold, a second intermediate-pressure inlet having a connection with said outlet manifold, a second check valve in said last-named connection, a second intermediatepressure outlet communicating with said second inlet, and a third high-pressure inlet connected with said outlet manifold, said third inlet being with respect to said second inlet on the downstream side of said second check valve, said second outlet and third inlet being connected by a passage located outside of the block.

3. High-pressure hydraulic apparatus comprising a pressure block, said block having an outlet manifold and a low-pressure inlet passage connected thereto, a first check valve connecting said inlet passage with said outlet manifold, said check valve opening only downstream from the inlet passage to the outlet manifold, manually controlled means for opening said valve against excess pressure in the outlet manifold over that in the inlet passage, a second intermediate-pressure inlet having a connection with said outlet manifold, a second check valve in said last-named connection, a second intermediate-pressure outlet communicating with said second inlet, and a third high-pressure inlet connecting with said,

outlet manifold, said third inlet being with respect to said second inlet on the downstream side of both of said check valves.

LUTWIN C. ROTTER. VICTOR G. KLEIN.

REFERENCES CITED The following references are of record in the file of this patent: 

